r333500 - Update NRVO logic to support early return
Taiju Tsuiki via cfe-commits
cfe-commits at lists.llvm.org
Tue May 29 20:53:17 PDT 2018
Author: tzik
Date: Tue May 29 20:53:16 2018
New Revision: 333500
URL: http://llvm.org/viewvc/llvm-project?rev=333500&view=rev
Log:
Update NRVO logic to support early return
Summary:
The previous implementation misses an opportunity to apply NRVO (Named Return Value
Optimization) below. That discourages user to write early return code.
```
struct Foo {};
Foo f(bool b) {
if (b)
return Foo();
Foo oo;
return oo;
}
```
That is, we can/should apply RVO for a local variable if:
* It's directly returned by at least one return statement.
* And, all reachable return statements in its scope returns the variable directly.
While, the previous implementation disables the RVO in a scope if there are multiple return
statements that refers different variables.
On the new algorithm, local variables are in NRVO_Candidate state at first, and a return
statement changes it to NRVO_Disabled for all visible variables but the return statement refers.
Then, at the end of the function AST traversal, NRVO is enabled for variables in NRVO_Candidate
state and refers from at least one return statement.
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: xbolva00, Quuxplusone, arthur.j.odwyer, cfe-commits
Differential Revision: https://reviews.llvm.org/D47067
Added:
cfe/trunk/test/CodeGenCXX/nrvo-noopt.cpp
cfe/trunk/test/SemaCXX/nrvo-ast.cpp
Modified:
cfe/trunk/include/clang/AST/Decl.h
cfe/trunk/include/clang/Sema/Scope.h
cfe/trunk/lib/Sema/Scope.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/lib/Sema/SemaStmt.cpp
cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
cfe/trunk/test/CodeGenCXX/nrvo.cpp
Modified: cfe/trunk/include/clang/AST/Decl.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Decl.h (original)
+++ cfe/trunk/include/clang/AST/Decl.h Tue May 29 20:53:16 2018
@@ -879,6 +879,12 @@ protected:
DAK_Normal
};
+ enum NRVOMode {
+ NRVO_Candidate,
+ NRVO_Disabled,
+ NRVO_Enabled,
+ };
+
class ParmVarDeclBitfields {
friend class ASTDeclReader;
friend class ParmVarDecl;
@@ -931,7 +937,7 @@ protected:
/// Whether this local variable could be allocated in the return
/// slot of its function, enabling the named return value optimization
/// (NRVO).
- unsigned NRVOVariable : 1;
+ unsigned NRVOMode : 2;
/// Whether this variable is the for-range-declaration in a C++0x
/// for-range statement.
@@ -1319,12 +1325,20 @@ public:
/// return slot when returning from the function. Within the function body,
/// each return that returns the NRVO object will have this variable as its
/// NRVO candidate.
+ NRVOMode getNRVOMode() const {
+ if (isa<ParmVarDecl>(this))
+ return NRVO_Disabled;
+ return static_cast<NRVOMode>(NonParmVarDeclBits.NRVOMode);
+ }
+ bool isNRVOCandidate() const {
+ return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.NRVOMode == NRVO_Candidate;
+ }
bool isNRVOVariable() const {
- return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.NRVOVariable;
+ return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.NRVOMode == NRVO_Enabled;
}
void setNRVOVariable(bool NRVO) {
assert(!isa<ParmVarDecl>(this));
- NonParmVarDeclBits.NRVOVariable = NRVO;
+ NonParmVarDeclBits.NRVOMode = NRVO ? NRVO_Enabled : NRVO_Disabled;
}
/// Determine whether this variable is the for-range-declaration in
Modified: cfe/trunk/include/clang/Sema/Scope.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Scope.h?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Scope.h (original)
+++ cfe/trunk/include/clang/Sema/Scope.h Tue May 29 20:53:16 2018
@@ -201,10 +201,6 @@ private:
/// Used to determine if errors occurred in this scope.
DiagnosticErrorTrap ErrorTrap;
- /// A lattice consisting of undefined, a single NRVO candidate variable in
- /// this scope, or over-defined. The bit is true when over-defined.
- llvm::PointerIntPair<VarDecl *, 1, bool> NRVO;
-
void setFlags(Scope *Parent, unsigned F);
public:
@@ -466,23 +462,7 @@ public:
UsingDirectives.end());
}
- void addNRVOCandidate(VarDecl *VD) {
- if (NRVO.getInt())
- return;
- if (NRVO.getPointer() == nullptr) {
- NRVO.setPointer(VD);
- return;
- }
- if (NRVO.getPointer() != VD)
- setNoNRVO();
- }
-
- void setNoNRVO() {
- NRVO.setInt(true);
- NRVO.setPointer(nullptr);
- }
-
- void mergeNRVOIntoParent();
+ void setNRVOCandidate(VarDecl *Candidate);
/// Init - This is used by the parser to implement scope caching.
void Init(Scope *parent, unsigned flags);
Modified: cfe/trunk/lib/Sema/Scope.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Scope.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/Scope.cpp (original)
+++ cfe/trunk/lib/Sema/Scope.cpp Tue May 29 20:53:16 2018
@@ -92,7 +92,6 @@ void Scope::Init(Scope *parent, unsigned
UsingDirectives.clear();
Entity = nullptr;
ErrorTrap.reset();
- NRVO.setPointerAndInt(nullptr, 0);
}
bool Scope::containedInPrototypeScope() const {
@@ -119,19 +118,15 @@ void Scope::AddFlags(unsigned FlagsToSet
Flags |= FlagsToSet;
}
-void Scope::mergeNRVOIntoParent() {
- if (VarDecl *Candidate = NRVO.getPointer()) {
- if (isDeclScope(Candidate))
- Candidate->setNRVOVariable(true);
+void Scope::setNRVOCandidate(VarDecl *Candidate) {
+ for (Decl *D : DeclsInScope) {
+ VarDecl *VD = dyn_cast<VarDecl>(D);
+ if (VD && VD != Candidate && VD->isNRVOCandidate())
+ VD->setNRVOVariable(false);
}
- if (getEntity())
- return;
-
- if (NRVO.getInt())
- getParent()->setNoNRVO();
- else if (NRVO.getPointer())
- getParent()->addNRVOCandidate(NRVO.getPointer());
+ if (Scope *parent = getParent())
+ parent->setNRVOCandidate(Candidate);
}
LLVM_DUMP_METHOD void Scope::dump() const { dumpImpl(llvm::errs()); }
@@ -191,9 +186,4 @@ void Scope::dumpImpl(raw_ostream &OS) co
OS << "MSCurManglingNumber: " << getMSCurManglingNumber() << '\n';
if (const DeclContext *DC = getEntity())
OS << "Entity : (clang::DeclContext*)" << DC << '\n';
-
- if (NRVO.getInt())
- OS << "NRVO not allowed\n";
- else if (NRVO.getPointer())
- OS << "NRVO candidate : (clang::VarDecl*)" << NRVO.getPointer() << '\n';
}
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Tue May 29 20:53:16 2018
@@ -1798,8 +1798,6 @@ static void CheckPoppedLabel(LabelDecl *
}
void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
- S->mergeNRVOIntoParent();
-
if (S->decl_empty()) return;
assert((S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) &&
"Scope shouldn't contain decls!");
@@ -12611,21 +12609,24 @@ Decl *Sema::ActOnStartOfFunctionDef(Scop
/// optimization.
///
/// Each of the variables that is subject to the named return value
-/// optimization will be marked as NRVO variables in the AST, and any
+/// optimization will be marked as NRVO variable candidates in the AST, and any
/// return statement that has a marked NRVO variable as its NRVO candidate can
/// use the named return value optimization.
///
-/// This function applies a very simplistic algorithm for NRVO: if every return
-/// statement in the scope of a variable has the same NRVO candidate, that
-/// candidate is an NRVO variable.
+/// This function applies a very simplistic algorithm for NRVO: if every
+/// reachable return statement in the scope of a variable has the same NRVO
+/// candidate, that candidate is an NRVO variable.
void Sema::computeNRVO(Stmt *Body, FunctionScopeInfo *Scope) {
- ReturnStmt **Returns = Scope->Returns.data();
+ for (ReturnStmt *Return : Scope->Returns) {
+ const VarDecl *Candidate = Return->getNRVOCandidate();
+ if (!Candidate)
+ continue;
- for (unsigned I = 0, E = Scope->Returns.size(); I != E; ++I) {
- if (const VarDecl *NRVOCandidate = Returns[I]->getNRVOCandidate()) {
- if (!NRVOCandidate->isNRVOVariable())
- Returns[I]->setNRVOCandidate(nullptr);
- }
+ if (Candidate->isNRVOCandidate())
+ const_cast<VarDecl*>(Candidate)->setNRVOVariable(true);
+
+ if (!Candidate->isNRVOVariable())
+ Return->setNRVOCandidate(nullptr);
}
}
@@ -12754,12 +12755,8 @@ Decl *Sema::ActOnFinishFunctionBody(Decl
else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(FD))
MarkVTableUsed(FD->getLocation(), Destructor->getParent());
- // Try to apply the named return value optimization. We have to check
- // if we can do this here because lambdas keep return statements around
- // to deduce an implicit return type.
- if (FD->getReturnType()->isRecordType() &&
- (!getLangOpts().CPlusPlus || !FD->isDependentContext()))
- computeNRVO(Body, getCurFunction());
+ // Try to apply the named return value optimization.
+ computeNRVO(Body, getCurFunction());
}
// GNU warning -Wmissing-prototypes:
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue May 29 20:53:16 2018
@@ -13385,13 +13385,9 @@ ExprResult Sema::ActOnBlockStmtExpr(Sour
if (Body && getCurFunction()->HasPotentialAvailabilityViolations)
DiagnoseUnguardedAvailabilityViolations(BSI->TheDecl);
- // Try to apply the named return value optimization. We have to check again
- // if we can do this, though, because blocks keep return statements around
- // to deduce an implicit return type.
- if (getLangOpts().CPlusPlus && RetTy->isRecordType() &&
- !BSI->TheDecl->isDependentContext())
- computeNRVO(Body, BSI);
-
+ // Try to apply the named return value optimization.
+ computeNRVO(Body, BSI);
+
BlockExpr *Result = new (Context) BlockExpr(BSI->TheDecl, BlockTy);
AnalysisBasedWarnings::Policy WP = AnalysisWarnings.getDefaultPolicy();
PopFunctionScopeInfo(&WP, Result->getBlockDecl(), Result);
Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Tue May 29 20:53:16 2018
@@ -3455,12 +3455,9 @@ Sema::ActOnReturnStmt(SourceLocation Ret
ExpressionEvaluationContext::DiscardedStatement)
return R;
- if (VarDecl *VD =
- const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
- CurScope->addNRVOCandidate(VD);
- } else {
- CurScope->setNoNRVO();
- }
+ VarDecl *VD =
+ const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate());
+ CurScope->setNRVOCandidate(VD);
CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Tue May 29 20:53:16 2018
@@ -1326,7 +1326,7 @@ ASTDeclReader::RedeclarableResult ASTDec
VD->NonParmVarDeclBits.IsThisDeclarationADemotedDefinition =
Record.readInt();
VD->NonParmVarDeclBits.ExceptionVar = Record.readInt();
- VD->NonParmVarDeclBits.NRVOVariable = Record.readInt();
+ VD->NonParmVarDeclBits.NRVOMode = Record.readInt();
VD->NonParmVarDeclBits.CXXForRangeDecl = Record.readInt();
VD->NonParmVarDeclBits.ObjCForDecl = Record.readInt();
VD->NonParmVarDeclBits.ARCPseudoStrong = Record.readInt();
Modified: cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriterDecl.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTWriterDecl.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTWriterDecl.cpp Tue May 29 20:53:16 2018
@@ -918,7 +918,7 @@ void ASTDeclWriter::VisitVarDecl(VarDecl
if (!isa<ParmVarDecl>(D)) {
Record.push_back(D->isThisDeclarationADemotedDefinition());
Record.push_back(D->isExceptionVariable());
- Record.push_back(D->isNRVOVariable());
+ Record.push_back(D->getNRVOMode());
Record.push_back(D->isCXXForRangeDecl());
Record.push_back(D->isObjCForDecl());
Record.push_back(D->isARCPseudoStrong());
@@ -2031,7 +2031,7 @@ void ASTWriter::WriteDeclAbbrevs() {
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
- Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
+ Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // NRVOMode
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isObjCForDecl
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isARCPseudoStrong
Added: cfe/trunk/test/CodeGenCXX/nrvo-noopt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/nrvo-noopt.cpp?rev=333500&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCXX/nrvo-noopt.cpp (added)
+++ cfe/trunk/test/CodeGenCXX/nrvo-noopt.cpp Tue May 29 20:53:16 2018
@@ -0,0 +1,58 @@
+// RUN: %clang_cc1 -emit-llvm -O0 -o - %s | FileCheck %s
+
+struct X {
+ X();
+ X(X&&);
+};
+
+// CHECK-LABEL: define void @_Z7test_00b
+X test_00(bool b) {
+ if (b) {
+ // CHECK-NOT: call void @_ZN1XC1EOS_
+ // CHECK: call void @_ZN1XC1Ev
+ // CHECK-NEXT: br label %return
+ X x;
+ return x;
+ } else {
+ // CHECK-NOT: call void @_ZN1XC1EOS_
+ // CHECK: call void @_ZN1XC1Ev
+ // CHECK-NEXT: br label %return
+ X x;
+ return x;
+ }
+}
+
+// CHECK-LABEL: define void @_Z7test_01b
+X test_01(bool b) {
+ if (b) {
+ // CHECK-NOT: call void @_ZN1XC1EOS_
+ // CHECK: call void @_ZN1XC1Ev
+ // CHECK-NEXT: br label %return
+ X x;
+ return x;
+ }
+ // CHECK-NOT: call void @_ZN1XC1EOS_
+ // CHECK: call void @_ZN1XC1Ev
+ // CHECK-NEXT: br label %return
+ X x;
+ return x;
+}
+
+// CHECK-LABEL: define void @_Z7test_02b
+X test_02(bool b) {
+ // CHECK: call void @_ZN1XC1Ev
+ X x;
+
+ if (b) {
+ // CHECK-NOT: call void @_ZN1XC1EOS_
+ // CHECK: call void @_ZN1XC1Ev
+ // CHECK-NEXT: br label %return
+ X y;
+ return y;
+ }
+
+ // CHECK-NOT: call void @_ZN1XC1Ev
+ // CHECK: call void @_ZN1XC1EOS_
+ // CHECK-NEXT: br label %return
+ return x;
+}
Modified: cfe/trunk/test/CodeGenCXX/nrvo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/nrvo.cpp?rev=333500&r1=333499&r2=333500&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/nrvo.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/nrvo.cpp Tue May 29 20:53:16 2018
@@ -130,17 +130,13 @@ X test2(bool B) {
}
// CHECK-LABEL: define void @_Z5test3b
-X test3(bool B) {
+X test3(bool B, X x) {
// CHECK: tail call {{.*}} @_ZN1XC1Ev
- // CHECK-NOT: call {{.*}} @_ZN1XC1ERKS_
- // CHECK: call {{.*}} @_ZN1XC1Ev
- // CHECK: call {{.*}} @_ZN1XC1ERKS_
if (B) {
X y;
return y;
}
- // FIXME: we should NRVO this variable too.
- X x;
+ // CHECK: tail call {{.*}} @_ZN1XC1ERKS_
return x;
}
@@ -191,9 +187,13 @@ X test6() {
}
// CHECK-LABEL: define void @_Z5test7b
+// CHECK-EH-LABEL: define void @_Z5test7b
X test7(bool b) {
// CHECK: tail call {{.*}} @_ZN1XC1Ev
// CHECK-NEXT: ret
+
+ // CHECK-EH: tail call {{.*}} @_ZN1XC1Ev
+ // CHECK-EH-NEXT: ret
if (b) {
X x;
return x;
@@ -202,10 +202,14 @@ X test7(bool b) {
}
// CHECK-LABEL: define void @_Z5test8b
+// CHECK-EH-LABEL: define void @_Z5test8b
X test8(bool b) {
// CHECK: tail call {{.*}} @_ZN1XC1Ev
// CHECK-NEXT: ret
- if (b) {
+
+ // CHECK-EH: tail call {{.*}} @_ZN1XC1Ev
+ // CHECK-EH-NEXT: ret
+if (b) {
X x;
return x;
} else {
@@ -221,4 +225,37 @@ Y<int> test9() {
// CHECK-LABEL: define linkonce_odr void @_ZN1YIiE1fEv
// CHECK: tail call {{.*}} @_ZN1YIiEC1Ev
+// CHECK-LABEL: define void @_Z6test10b
+X test10(bool B, X x) {
+ if (B) {
+ // CHECK: tail call {{.*}} @_ZN1XC1ERKS_
+ // CHECK-EH: tail call {{.*}} @_ZN1XC1ERKS_
+ return x;
+ }
+ // CHECK: tail call {{.*}} @_ZN1XC1Ev
+ // CHECK-NOT: call {{.*}} @_ZN1XC1ERKS_
+
+ // CHECK-EH: tail call {{.*}} @_ZN1XC1Ev
+ // CHECK-EH-NOT: call {{.*}} @_ZN1XC1ERKS_
+ X y;
+ return y;
+}
+
+// CHECK-LABEL: define {{.*}} void @_Z6test11I1XET_v
+// CHECK-EH-LABEL: define {{.*}} void @_Z6test11I1XET_v
+template <typename T>
+T test11() {
+ // CHECK: tail call {{.*}} @_ZN1XC1Ev
+ // CHECK-NEXT: ret void
+
+ // CHECK-EH: tail call {{.*}} @_ZN1XC1Ev
+ // CHECK-EH-NEXT: ret void
+ T t;
+ return t;
+}
+
+void test12() {
+ test11<X>();
+}
+
// CHECK-EH-03: attributes [[NR_NUW]] = { noreturn nounwind }
Added: cfe/trunk/test/SemaCXX/nrvo-ast.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/nrvo-ast.cpp?rev=333500&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/nrvo-ast.cpp (added)
+++ cfe/trunk/test/SemaCXX/nrvo-ast.cpp Tue May 29 20:53:16 2018
@@ -0,0 +1,139 @@
+// RUN: %clang_cc1 -fcxx-exceptions -fsyntax-only -ast-dump -o - %s | FileCheck %s
+
+struct X {
+ X();
+ X(const X&);
+ X(X&&);
+};
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_00
+X test_00() {
+ // CHECK: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ return x;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_01
+X test_01(bool b) {
+ // CHECK: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ if (b)
+ return x;
+ return x;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_02
+X test_02(bool b) {
+ // CHECK-NOT: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ // CHECK-NOT: VarDecl {{.*}} y {{.*}} nrvo
+ X y;
+ if (b)
+ return y;
+ return x;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_03
+X test_03(bool b) {
+ if (b) {
+ // CHECK: VarDecl {{.*}} y {{.*}} nrvo
+ X y;
+ return y;
+ }
+ // CHECK: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ return x;
+}
+
+extern "C" _Noreturn void exit(int) throw();
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_04
+X test_04(bool b) {
+ {
+ // CHECK: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ if (b)
+ return x;
+ }
+ exit(1);
+}
+
+void may_throw();
+// CHECK-LABEL: FunctionDecl {{.*}} test_05
+X test_05() {
+ try {
+ may_throw();
+ return X();
+ } catch (X x) {
+ // CHECK-NOT: VarDecl {{.*}} x {{.*}} nrvo
+ return x;
+ }
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_06
+X test_06() {
+ // CHECK-NOT: VarDecl {{.*}} x {{.*}} nrvo
+ X x __attribute__((aligned(8)));
+ return x;
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_07
+X test_07(bool b) {
+ if (b) {
+ // CHECK: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ return x;
+ }
+ return X();
+}
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_08
+X test_08(bool b) {
+ if (b) {
+ // CHECK: VarDecl {{.*}} x {{.*}} nrvo
+ X x;
+ return x;
+ } else {
+ // CHECK: VarDecl {{.*}} y {{.*}} nrvo
+ X y;
+ return y;
+ }
+}
+
+template <typename T>
+struct Y {
+ Y();
+ // CHECK-LABEL: CXXMethodDecl {{.*}} test_09 'Y<T> ()'
+ // CHECK: VarDecl {{.*}} y 'Y<T>' nrvo
+
+ // CHECK-LABEL: CXXMethodDecl {{.*}} test_09 'Y<int> ()'
+ // CHECK: VarDecl {{.*}} y 'Y<int>' nrvo
+ static Y test_09() {
+ Y y;
+ return y;
+ }
+};
+
+struct Z {
+ Z(const X&);
+};
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_10 'A ()'
+// CHECK: VarDecl {{.*}} b 'B' nrvo
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_10 'X ()'
+// CHECK: VarDecl {{.*}} b {{.*}} nrvo
+
+// CHECK-LABEL: FunctionDecl {{.*}} test_10 'Z ()'
+// CHECK-NOT: VarDecl {{.*}} b {{.*}} nrvo
+template <typename A, typename B>
+A test_10() {
+ B b;
+ return b;
+}
+
+void instantiate() {
+ Y<int>::test_09();
+ test_10<X, X>();
+ test_10<Z, X>();
+}
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